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To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.dsr.2007.03.002 Byline: David Thistle (a), Linda Sedlacek (a), Kevin R. Carman (b), John W. Fleeger (b), James P. Barry (c) Keywords: Benthos; Emergence; Harpacticoida; Meiofauna; Ocean floor; USA; California; Continental slope; 36[degrees]41.91'N 123[degrees]0.14'W Abstract: In coastal waters, individuals of many benthic species make temporary excursions into the water column, a behavior called emergence. The reasons for this behavior are not well established, but some that have been suggested apply equally well to the deep sea, and some sediment-trap data suggest that emergence occurs in the deep sea. To investigate this possibility, we collected sediment cores and placed inverted-funnel traps at 3087m depth on the continental slope off central California (36[degrees]41.91'N 123[degrees]0.14'W) for 36 days and investigated a representative taxon, the harpacticoid copepods. Although our methods probably produced underestimates, at least 4 of 55 species emerged, so conceptualizations about the ecology of deep-sea-sediment communities should include the idea that some benthic species use the near-bottom flow to change locations. Author Affiliation: (a) Department of Oceanography, Florida State University, Tallahassee, FL 32306-4320, USA (b) Department of Biological Sciences, Louisiana State University, Baton Rouge, LA 70803-1725, USA (c) Monterey Bay Aquarium Research Institute, Sandholdt Road, Moss Landing, CA 95039-9644, USA Article History: Received 31 March 2006; Revised 26 February 2007; Accepted 9 March 2007

On 20 April 2010, the Deepwater Horizon explosion, which released a US government-estimated 4.9 million barrels of crude oil into the Gulf of Mexico, was responsible for the death of 11 oil workers and, possibly, for an environmental disaster unparalleled in US history. For 87 consecutive days, the Macondo well continuously released crude oil into the Gulf of Mexico. Many kilometers of shoreline in the northern Gulf of Mexico were affected, including the fragile and ecologically important wetlands of Louisiana's Mississippi River Delta ecosystem. These wetlands are responsible for a third of the nation's fish production and, ironically, help to protect an energy infrastructure that provides a third of the nation's oil and gas supply. Here, we provide a basic overview of the chemistry and biology of oil spills in coastal wetlands and an assessment of the potential and realized effects on the ecological condition of the Mississippi River Delta and its associated flora and fauna. [ABSTRACT FROM AUTHOR]

High irradiation and the presence of xenobiotics favor the formation of reactive oxygen species in marine environments. Organisms have developed antioxidant defenses, including the accumulation of carotenoids that must be obtained from the diet. Astaxanthin is the main carotenoid in marine crustaceans where, among other functions, it scavenges free radicals thus protecting cell compounds against oxidation. Four diets with different carotenoid composition were used to culture the meiobenthic copepod Amphiascoides atopus to assess how its astaxanthin content modulates the response to prooxidant stressors. A. atopus had the highest astaxanthin content when the carotenoid was supplied as astaxanthin esters (i.e., Haematococcus meal). Exposure to short wavelength UV light elicited a 77% to 92% decrease of the astaxanthin content of the copepod depending on the culture diet. The LC50 values of A. atopus exposed to copper were directly related to the initial astaxanthin content. The accumulation of carotenoids may ascribe competitive advantages to certain species in areas subjected to pollution events by attenuating the detrimental effects of metals on survival, and possibly development and fecundity. Conversely, the loss of certain dietary items rich in carotenoids may be responsible for the amplification of the effects of metal exposure in consumers. [ABSTRACT FROM AUTHOR]

Estuarine sediment microcosms were treated with combinations of diesel, copper (at two levels), and a mixture of heavy metals (mercury, cadmium, lead, and chromium; at two levels) mimicking the contaminant loadings found in harbor sediments. The effects on the microbial community were monitored by polar lipid fatty acid analysis. Diesel addition increased microbial biomass, caused shifts in some fatty acid structural groups, and decreased starvation biomarkers. Incorporation of diesel hydrocarbons into lipids was expressed as an increase in the proportion of odd-carbon-number fatty acids. No treatment with the metals mixture (mercury, cadmium, lead, and chromium) alone significantly changed any parameter derived from the polar lipid fatty acids, but the increase in microbial biomass from diesel addition was higher with the metals mixture, possibly because of indirect effects caused by reductions in grazing resulting from metal-induced toxicity to bacteriovorous nematodes. Copper also modified the effects of diesel addition, preventing biomass increase but not diesel degradation, suggesting that some of the energy gained from diesel oxidation was expended combating copper toxicity. In the present study, observations indicate that metals in general, and copper in particular, can modify the response of sedimentary microorganisms to petroleum-hydrocarbon contaminants. [ABSTRACT FROM AUTHOR]

University of Nevada, Reno Executive Vice President and Provost expresses his appreciation to organizers of and participants in the 2019 Rhetoric Society of America Project in Power, Place, and Publics (RSA Project), which was hosted on the University of Nevada, Reno campus. The RSA Project critically evaluated the 2014 UNR Campus Master Plan (CMP) and provided insights on how future updates of the CMP can be more responsive to community stakeholders whose voices are often not heard. [ABSTRACT FROM AUTHOR]

Examines the effects of grazing and nitrogen availability on benthic algal blooms in diesel-fuel contaminated saltmarsh sediments. Microalgal biomass sediments with reduced grazing period; Influence of excessive nitrogen on algal growth in contaminated and uncontaminated sediments; Implications of the study on ecological health.

Microcosm experiments addressed the impact of a mixture of Cu, Cr, Cd, Pb, and Hg at three concentrations after 36 h, 12 d, and 30 d on ameiofauna-dominated salt marsh community. In addition to analyzing effects on meiofaunal abundances, the study quantified the sediment metal concentrations of all five metals and pore-water concentrations, speciation, and ligand complexation of Cu. Abundances of deposit feeders such as the polychaete Streblospio benedicti, gastropods, and bivalves were impacted at lower metal concentrations than the mainly algal-feeding copepods, ostracods, and nematodes. We suggest that this might be due to bulk ingestion of metal-contaminated sediments resulting in relatively higher metal exposure in the deposit feeders than inthe other, nondeposit feeding taxa. Copepod and ostracod abundances decreased only in the highest metal treatment, where levels of inorganic Cu ([Cu']) in pore waters were similar to levels associated with both acute and subacute toxicity in published in vivo toxicity studies of marine copepods. The higher metal treatments yielded disproportionately higher pore-water [Cu] compared with sediment [Cu], suggesting saturation of sediment-associated ligands with increased additions of Cu. Similarly, the higher metal treatments appeared to reach saturation of the organic Cu ligands, with the excess pore-water [Cu] present in the more toxic, inorganic species of Cu. Acid-volatile sulfide(AVS) concentrations at sediment horizons inhabited by meiofauna were low and AVS was not considered a significant metal ligand at these depths. Since meiofauna are predominantly associated with oxic surface sediments, it is doubtful that AVS is a major factor controlling availability of free metal for exposure to these taxa. [ABSTRACT FROM AUTHOR]

Microsporidia constitute a large group of obligate intracellular protozoan parasites that inject themselves into host cells via the extrusion apparatus of the infective spore stage. Although the injection process is poorly understood, its energy source is thought to reside in the posterior vacuole that swells significantly during spore firing. Here we report the presence and localisation of the key peroxisomal enzymes catalase and acyl-CoA oxidase (ACOX) within the posterior vacuole of Spraguea lophii (Doflein, 1898) spores. Western blot analyses show that these enzymes discharge out of the spore and end up in the medium external to the extruded sporoplasms. The presence of a catalase enzyme system in the Microsporidia was first made evident by the detection of significant levels of molecular oxygen in the medium containing discharging spores in the presence of hydrogen peroxide. Catalase was visualised in inactive, activated, and discharged spores using alkaline diaminobenzidine (DAB) on glutaraldehyde-fixed cells. The position of these enzymes within the extrusion apparatus before and during spore discharge support the Lom and Vávra model that postulates discharge occurs by an eversion process. In addition to these enzymes, spores of S. lophii contain another characteristic peroxisomal component, the very long chain fatty acid (VLCFA) nervonic acid. A sizeable decrease in nervonic acid levels occurs during and after spore discharge. These data indicate that nervonic acid is discharged from the spore into the external medium during firing along with the catalase and ACOX enzymes.